In recent years, there have been increasing demands for improvement in color photographic papers as to rapid processing performance and accordingly much research has been done to this end. It is known that raising the silver chloride content of a silver halide emulsion leads to notable improvement in developing speed, as disclosed in, for example, International Patent WO87-04534. In the market place, the emulsions used for the color photographic paper are formulated to have a higher silver chloride content.
In these light-sensitive materials for color photographic papers, color reproducibility of the finished dye image as well as rapidity in processing is important in terms of quality. The performance of a color negative photographic film depends largely on the hue of the developed dyes which form the print image. The hue of the developed dyes also determines the broad color reproduction area, that is, a color print so obtained can have what true reproduced image can be formed based on the original to be reproduced. Silver halide color photographic light-sensitive print materials having excellent color reproducibility have been studied from various standpoints. In a conventional light-sensitive material for a color print, there is generally applied a color reproduction system based on the subtractive color process in which cyan, magenta and yellow colors are used as the primary three colors. The process is restricted by the absorption characteristics of the cyan, magenta and yellow dyes used, i.e., how truly and in what broad range the colors can be reproduced in the color print. Where the light absorption profile of the dye is broad and undesirable side-absorptions are involved, a color turbidity is generated.
In view of the above it is known that conventional phenol series or naphthol series couplers have problems in forming a cyan dye image with a usual light-sensitive material for a color print, since they have side-absorptions in the green and blue regions. Therefore, they are not preferred in reproducing the said colors, and a solution thereof has been desired.
An example of an unnecessary side-absorption deteriorating the color reproduction is that the green color of, for example, a green leaf which is photographed on a color negative film and reproduced on a color print inclines to a brownish green color in some cases.
As the means for solving this problem, 2,4-diphenylimidazoles described in European Patent 294,453A2 are proposed. In the dyes formed by these couplers, undesirable side-absorption in short wavelength regions is reduced compared with that of conventional dyes. Accordingly, they are preferable in terms of color reproduction.
However, in these couplers, the color reproduction is not necessarily sufficient and additionally, there remain the problems that in practical use coupling activity is low and that fastness to heat and light is poor. Accordingly, they are impractical.
The pyrazoloazole series couplers described in JP-A-64-553 (the term "JP-A" as used herein means an unexamined published Japanese patent) are improved as to side-absorption in short wavelength regions compared with that of conventional dyes, but those couplers do not always have sufficient color reproducibility and there remains the problem that color developing performance is notably low.
The development of a cyan coupler having an excellent color reproduction by the present inventors has resulted in finding that dyes having reduced unfavorable side-absorptions in the green and blue regions can be formed with the following pyrroloazole-type cyan dye-forming couplers having the specified substituent groups, and that great improvements in color reproduction can be achieved therewith.
However, the preparation and evaluation of color light-sensitive materials in which the cyan dye-forming coupler having this pyrroloazole primary nucleus is used in combination with a high silver chloride emulsion has resulted in the finding of a serious practical problem which has not been anticipated. That is, the silver halide color photographic light-sensitive material can surely provide a cyan dye image having a high color purity, but the various processing tests carried-out under retail market color lab, development processing conditions (a processing station) have revealed the problem of large changes (of the cyan dye portion) photographic performance due to compositional changes in processing solutions.
Further, detailed inspection of the cause of this composition change in the processing solution has revealed that the degree of mixing of the bleach-fixing solution into the developing solution corresponds to this change (of the cyan dye portion) in photographic performance.
Low replenishing and low discharging of processing solutions is the current trend from the viewpoint of environmental problems and overcoming the defects inherent in such processing methods is an important subject in developing a photographic light-sensitive material.
With respect to the above mixing of the bleach-fixing solution into the developing solution, it is almost impossible to completely prevent the mixing thereof, even by strict management for preventing such mixing at retail market labs (the processing station) because of the splash of the solutions. Further, another problem exists in that the amount of the bleach-fixing solution mixed into the developing solution is varied to a large extent from lab to lab, depending on the method of transport with rollers and squeezing in an automatic developing machine and the differences in processing amounts per unit time. The recent inclination toward low replenishing of solutions is accompanied by further increases in such mixing trend. As it is indispensable in practical use to give consistently stable photographic performance at any market labs, it is necessary to minimize the change in the photographic characteristics due to the degree of mixing of the bleach-fixing solution into the developing solution.
In this regard, a method in which the layer having a relatively high silver bromide content is formed on the outermost layer of a high silver chloride grain is disclosed in JP-A-62-254139, but such level meeting a sufficiently practical use has not been achieved, even with this technique.
It is disclosed in, for example, JP-A-60-222845 that in order to provide a high silver chloride emulsion with a high sensitivity, it is effective to allow the emulsion to have various grain constitutions in which a phase having a high silver bromide content is provided in the silver halide grains. However, the results of the investigations made by the present inventors revealed that continuous processing carried out for a silver halide light-sensitive material in which there is used a silver bromochloride emulsion which is highly sensitized by giving the above-mentioned silver bromide-rich phase; was liable to soften the gradation of the cyan color developed portion, particularly at the high density portion with the density of 1.8 or more. This is not preferable since it allows the black portion of an image formed thereon to incline to red and an image to become unstable. Further, it was found that the more the replenishing amount of a development processing solution was reduced, the more notable this tendency became. When the replenishing amount of the development processing solution is reduced, the substances eluted from the light-sensitive material, that is, the halide ions and other ions generated upon developing, and various additives contained in the light-sensitive material were increased in the accumulated amounts thereof, and the compositional change in the processing solution becomes notable. Accordingly, the above softening of the developed cyan color is assumed to be due to this compositional change.
Further, it is found that where the light-sensitive material in which the silver halide emulsion provided with a sliver bromide-rich phase is used is continuously processed, a so-called desensitization stripe in which a portion to which a pressure may be exerted in a processing solution is desensitized, the density thereof is lowered and it is liable to generate desensitization stripes that markedly damage image quality.
There is disclosed in JP-A-2-96150, a technique in which a high silver chloride emulsion provided with a silver bromide-localized phase and a specific processing can be combined to decrease the change in a photographic performances before and after continuous processing. However, the results of the investigations repeated by the present inventors reveal that the change in photographic performances can certainly be reduced, but not necessarily sufficiently and further the generation of the desensitization stripes as described above can not be decreased.
In the case of a light-sensitive material for a color photographic paper, many prints have to be presented at a short delivery date with stable and uniform photographic performances. Accordingly, the light-sensitive material is continuously processed with an automatic developing machine. There is also the problem that calcium deposited on rollers during processing damages the surface of the light-sensitive material and therefore, stable and uniform photographic performances can not be maintained.
Calcium which may deposit on rollers during processing is released from the light-sensitive material (contained mainly in gelatin) to the processing solutions. Therefore, it is desirable to reduce the calcium content in the light-sensitive material as much as possible. Meanwhile, there exists the problem of deterioration of emulsion sensitivity including a coating solution, prepared by using gelatin, the calcium content of which is reduced as much as possible, upon several hours storage; particularly in the case of a coating solution comprising a red-sensitive emulsion, spectrally sensitized to a red color region, and a cyan dye-forming coupler. The reduction in calcium content required to overcome the instability in manufacturing performance and the technical development therefor was necessary.